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Finding the Fourth Proportional to 821.79, 1,232.69 and 638.66

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Solution

The fourth proportional to 821.79, 1,232.69 and 638.66 is: 957.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    821.79 : 1,232.69 = 638.66 : x
  2. Step 2: Convert to fraction form
    821.79/1,232.69 = 638.66/x
  3. Step 3: Cross multiply
    821.79x = 1,232.69 × 638.66
  4. Step 4: Simplify right side
    821.79x = 787,269.68
  5. Step 5: Solve for x
    x = 787,269.68/821.79
  6. Step 6: Final answer
    x = 957.99

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.